The subject matter of the present invention relates generally to athletic shoes and in particular to athletic shoes having multi-layered soles including an apertured sole layer and/or a foam core sole layer positioned between a harder, wear resistant outer sole layer and the shoe upper.
In the preferred embodiment, the apertured sole layer is a heel lift layer positioned below an intermediate sole layer having a softer resilient foam core surrounded by a harder resilient border portion and provided within an elongated opening extending longitudinally beneath the heel, arch and metatarsal bones of the wearer's foot for greater comfort and support. The shoe is built on a straight last and is provided with flared sides on the intermediate sole layer and heel lift layer for greater lateral stability along with a flat planar beveled heel which insures proper foot position during initial contact with the ground, sometimes called "heel strike." This insures proper foot placement from heel strike to toe off. The shoe of the present invention is especially useful as a training shoe for running, exercise and conditioning, since it prevents injury to the foot and leg.
Previously it has been proposed in spike track shoes used by jumpers, to provide an aperture in the heel lift sole layer for cushioning the heel, as shown in U.S. Pat. No. 3,290,801 of Bente, granted Dec. 13, 1966. However, such shoes employed a single opening in the heel lift layer of a sufficient size to receive the downward projection of the heel bone of the foot to prevent injury to the heel of the jumper. It is also old to provide conventional street shoes with an apertured middle sole for ventilation, as shown in U.S. Pat. No. 231,398 of Bussey, granted Aug. 24, 1880 and U.S. Pat. No. 3,050,875 of Robbins, granted Aug. 28, 1962. Unlike the present invention, a plurality of apertures arranged in three staggered rows are not provided in the heel lift layer to provide both support and cushioning. In addition, there is no intermediate sole layer provided above the heel lift layer which contains a softer resilient foam core within an elongated opening extending beneath the heel, arch and metatarsal bones of the foot as is employed in the training shoe of the present invention. Furthermore, there is no indication that such athletic shoe should be made with a straight last. However, it should be noted that conventional street shoes have previously been made with straight lasts, as shown in U.S. Pat. No. 2,034,243 of Maxwell, granted Mar. 17, 1936.
Previously it has been proposed in U.S. Pat. No. 3,793,750 of Bowerman to provide an athletic shoe with a nylon fabric upper and cushion middle sole layer covered by a harder outer sole including polygon-shaped studs. Athletic shoes have also been made with flared sides and beveled rear heel surfaces. Unlike the present invention, such athletic shoes were not provided with an apertured heel lift layer or an intermediate sole layer having an inserted core of softer foam cushioning. These sole layers give the athletic shoe of the present invention the advantages of excellent comfort and support, while at the same time providing a relatively lightweight shoe of long useful lifetime and good traction.